Recent news that Happy, a 34-year-old Asian elephant, recognized herself in a giant, shatter-proof mirror at the Bronx Zoo is just the latest in a burgeoning list of eye-opening revelations into the minds and motivations of other beings.

Recent studies have shown that mice empathize with familiar mice who are suffering, that captive male monkeys will hand over a bottle of fruit juice for a chance to ogle photos of female monkeys' bottoms and that rats accustomed to being tickled will come running for more, making high-pitched chirps linked to the origins of human laughter.

Such discoveries are not confined to mammals. Pigeons navigate using human roads, ravens slide or roll down snow banks just for kicks and iguanas will shun boring food to brave the cold for a gourmet treat.

Fish, too, can no longer be dismissed as mindless, unfeeling things. Three fish biologists recently described fishes as: ``steeped in social intelligence, pursuing Machiavellian strategies of manipulation, punishment, reconciliation and cooperation.''

The once-long list of uniquely human traits is dwindling almost as fast as you can say ''human supremacy.'' Tool use, a former symbol of our unique ingenuity, is widespread in nature, and several species manufacture and modify their own tools. Animals also have their own cultures, and they may show malice, or compassion, for others. They deceive, tease, pretend and celebrate, and they exhibit a broad range of emotions including grief, gratitude, jealousy, joy and embarrassment.

We aren't even the best at everything. Our sense of smell pales in comparison to that of most mammals. Bats interpret echoes with a precision that our best sonar can't come close to emulating. Some animals use geomagnetic, electrical, seismic or celestial cues. Pigeons outscore humans at recognizing objects rotated at different angles. Chimps were thought to have poor face-recognition skills -- until someone thought to present them with pictures of faces from their own species instead of human faces.

Unfortunately, as our knowledge and understanding of animal awareness and sentience advances, our treatment of them lags further behind. We kill tens of billions of animals yearly, and the toll is rising. In just the time it takes you to read this sentence, a thousand factory-farmed chickens will have been slaughtered in the United States. Like most farmed animals today, they are deprived of the freedom to move about, fresh air to breathe and the sun on their backs.

Another hundred million animals languish in tiny laboratory cages and suffer in harmful experiments and product tests. Those who don't die are usually killed. Tens of millions more are killed for fashion, recreation and entertainment. The numbers strain comprehension. But science and common sense tell us that every one of these animals is a thinking, feeling individual.

Because animals are sentient -- because they can feel fear and pain, pleasure and joy -- it follows that to them, their lives have value. It matters little what their IQ is. Their pain and pleasure are akin to yours and mine, and their will to live is just as strong.

If animals experience the world essentially as we do, can we really justify harming and killing them for our own interests?

Jonathan Balcombe is an ethologist and Research Scientist with the Physicians Committee for Responsible Medicine, in Washington, D.C. and author of Pleasurable Kingdom: Animals and the Nature of Feeling Good.